Implantable medical device and method for managing a physical layer utilized during a wireless connection

ABSTRACT

An implantable medical device, external device and method for managing a wireless communication are provided. The IMD includes a transceiver configured to communicate wirelessly, with an external device (ED), utilizing a protocol that utilizes multiple physical layers. The transceiver is configured to transmit information indicating that the transceiver is configured with first, second, and third physical layers (PHYs) for wireless communication. The IMD includes memory configured to store program instructions. The IMD includes one or more processors configured to execute instructions to obtain an instruction designating one of the first, second and third PHY to be utilized for at least one of transmission or reception, during a communication session, with the external device and manage the transceiver to utilize, during the communication session, the one of the first, second and third PHY as designated.

BACKGROUND

Embodiments of the present disclosure generally relate to techniques formanaging wireless communication with implantable medical devices, andmore particularly to the utilization of various physical layers duringwireless communication.

An implantable medical device (IMD) is a medical device that isconfigured to be implanted within a patient anatomy and commonly employsone or more electrodes that either receive or deliver voltage, currentor other electromagnetic pulses from or to an organ or tissue fordiagnostic or therapeutic purposes. In general, IMDs include a battery,electronic circuitry, a pulse generator, a transceiver and/or amicroprocessor that is configured to handle communication with anexternal device as well as control patient therapy. The IMD iscompletely enclosed within the human body. Thus, there is no means ofdirect interaction with an IMD, other than through wirelesscommunication.

However, IMDs are typically built with non-replaceable batteries thatlimit options for communications solutions. Typically, the wirelesscommunication is maintained utilizing a low range, low powercommunications platform during short periods of time. Existingcommunication solutions experience certain limitations regarding datatransmission efficiency and rate. Currently, Bluetooth low energy (BLE)enabled IMDs use a static Bluetooth physical layer (PHY) and data rateduring BLE communication irrespective of the type of transmission or howmuch data is being transferred. The standard settings are PHY=LE 1 Mwith a data rate of 1 Mb/s. Using a common standard data rate for alltransmissions throughout the life of an IMD is highly inefficient giventhat, for at least a portion of the time, the IMD is sending orreceiving small amounts of data such as alerts and commands. Further,certain types of devices, such as miniature implantable medical devices,are more likely to send/receive alerts, commands or other smaller datasets. Miniature implantable medical devices have significantrestrictions on battery demand which require that larger data transfershappen very infrequently. The foregoing are only a few examples of whydifferent types of communications sessions are better suited to utilizedifferent data rates and error correction schemes.

An ongoing demand exists to reduce power usage by IMDs. By limitingpower usage, IMDs are able to last longer and be constructed with asmaller form factor. IMDs use a relatively large amount of power inconnection with transmit and receive operations for BLE communications.Reducing the power usage for transmitting and receiving, however, willconflict with a separate demand for acceptable BLE communicationdistance. Creating and maintaining a strong BLE connection at anacceptable distance requires significant power consumption by the BLEtransceiver.

Previously, it has been proposed to reduce the power demand by an IMDthrough defining an advertising schedule that uses different transmitpower schemes. In accordance with at least one solution, methods andsystems have been proposed that save power usage by defining anadvertising schedule that includes a first transmit power setting whenan external device (ED), communicating with an IMD, is in closeproximity and a second transmit power setting when the ED is at afurther distance. With the advancement of Bluetooth technology to theBluetooth 5.0 standard, new opportunities are available for improvingreceiver sensitivity in order to conserve power consumption while at thesame time optimizing communication distance.

BRIEF SUMMARY

In accordance with aspects herein, methods and devices are described toadaptively change transmission data rates and physical layers (PHY) toimprove current consumption and/or RF performance. Using other PHYs cangive advantages such as higher data rates or forward error correction(FEC) coding. Using lower data rates increases the ability of animplantable medical device and an external device to correctly receiveeach other's signal (improved receiver sensitivity) which effectivelyincreases the communication range. Increasing receiver sensitivity meansthe corresponding transmit power levels can be decreased which savespower.

In accordance with new and unique aspects herein, methods and devicesare described that use the lowest data rate for lower payloadtransmissions such as alerts and commands. This in turn creates astronger communications connection so that either (1) the communicationdistance can be extended or (2) for the same communication distance, thetransmit power can be reduced to save battery life. When data transfersor firmware updates are necessary, the BLE radios will switch back tothe higher data rate momentarily until the transfers and updates arecomplete. Also, in addition to switching data rates, the methods anddevices herein switch physical layers to provide additional benefits ontop of the data rates.

In accordance with embodiments herein, an implantable medical device(IMD) is provided. The IMD includes a transceiver configured tocommunicate wirelessly, with an external device (ED), utilizing aprotocol that utilizes multiple physical layers. The transceiver isconfigured to transmit information indicating that the transceiver isconfigured with first, second, and third physical layers (PHYs) forwireless communication. The IMD includes memory configured to storeprogram instructions. The IMD includes one or more processors configuredto execute instructions to obtain an instruction designating one of thefirst, second and third PHY to be utilized for at least one oftransmission or reception, during a communication session, with theexternal device and manage the transceiver to utilize, during thecommunication session, the one of the first, second and third PHY asdesignated.

Optionally, the transceiver may be configured to transmit acommunications packet to represent at least one of an advertisementpacket, a scan request packet, or a scan response packet. Thecommunications packet may include the information indicating that thetransceiver is configured with the first, second and third PHYs. Thetransceiver may be configured to receive an ED communications packetfrom the external device. The ED communications packet may include theinstruction designating the one of the first, second and third PHY. Theone or more processors may be configured to at least one of 1) determinethe type of communication or 2) determine a size of data set to betransferred between the ED and IMD. The one or more processors may beconfigured to generate the instruction designating the one of the first,second and third PHYs based on at least one of the type of communicationor the size of the data set.

Optionally, the protocol may correspond to a Bluetooth protocol. Thefirst, second and third PHY may correspond to LE 1 M, LE 2 M and LECoded PHYs, respectively. The instruction may designate the LE 2 M PHYwhen the type of communication corresponds to a large payloadcommunication. The instruction may designate the LE Coded PHY when thetype of communication corresponds to a small payload communication. Theone or more processors may be configured to manage a receiver of thetransceiver to utilize the first PHY in connection with receivingcommunications packets from the ED and may manage a transmitter of thetransceiver to utilize the second PHY in connection with transmittingcommunications packets to the ED.

In accordance with embodiments herein, an external device (ED)configured to wirelessly communicate with an implantable medical device(IMD) utilizing a protocol that supports multiple physical layers (PHYs)is provided. The ED includes an external transceiver configured towirelessly communicate with the IMD. The external transceiver isconfigured to receive a communications packet. The ED includes memoryconfigured to store program instructions. The ED includes one or moreprocessors that are configured, when implementing the programinstructions, to analyze the communications packet for informationindicating whether the IMD is configured with multiple physical layers(PHYs) for wireless communication, select one of the multiple PHYs basedon at least one of a type of communication to occur, or a size of a dataset to be transferred, during a communication session and transmit aninstruction to the IMD to utilize the one of the multiple PHYs selectedfor at least one of transmission or reception during the communicationsession.

Optionally, the one or more processors may be further configured toreceive, as the communications packet, an advertisement packet, andanalyze a content of the advertisement packet for the informationindicating where the IMD is configured with the multiple PHYs. Theinformation analyzed from the communications packet may indicate whetherthe IMD is compatible with Bluetooth version 5.0 or higher. The one ormore processors may be configured to determine the type of communicationand select between first or second PHY based on the type ofcommunication. The one or more processors may be configured to determinethe size of the data set to be transferred and select between the secondPHY or a third PHY based on the size of the data set to be transferred.

Optionally, following the select and transmit operations, the one ormore processors may be configured to manage the external transceiver toestablish a communication session with the IMD utilizing the one of themultiple PHYs. The one or more processors may be configured to initiatea communication session utilizing a first PHY from the multiple PHY and,to change, during the communication session, to a second PHY from themultiple PHY. The one or more processors may change to the second PHYbased on a connection criteria that includes at least one of a datathroughput requirement, a communication type, a battery indicator, atelemetry break condition, or link condition of the communications linkbetween the IMD and ED.

In accordance with embodiments herein, a method for managing a wirelesscommunication between an external device (ED) and an implantable medicaldevice (IMD) utilizing a protocol that supports multiple physical layers(PHYs) is provided. The method selects, at one of the ED or IMD, one ofmultiple PHYs for wireless communication based on a connection criteria.The method transmits an instruction, to another of the ED or IMD, toutilize the one of the multiple PHYs selected for at least one oftransmission or reception during the communication session.

Optionally, the method may receive, at the ED, a communications packetfrom the IMD and may analyze the communications packet for informationindicating whether the IMD is configured with multiple physical layers(PHYs) for wireless communication. The ED may perform the selecting theone of the multiple PHYs and transmitting the instruction to the IMD.The method may collect and analyze the connection criteria. Theconnection criteria may include at least one of a data throughputrequirement, a communication type, a battery indicator, a telemetrybreak condition, or link condition of a communications link between theIMD and ED. The method may determine at least one of 1) a type ofcommunication or 2) a size of the data set to be transferred, and basedthereon selecting the one of the multiple PHYs. The method may establisha communication session between the ED and the IMD utilizing the one ofthe multiple PHYs. The method pay initiate a communication sessionutilizing a first PHY from the multiple PHY and, changing, during thecommunication session, to a second PHY from the multiple PHY.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a simplified block diagram of a system operated inaccordance with embodiments herein.

FIG. 2A illustrates a block diagram of communication circuitry utilizedin accordance with an embodiments herein.

FIG. 2B illustrates a full protocol stack structure of a Bluetoothprotocol in accordance with an embodiments herein.

FIG. 3 illustrates a distributed processing system in accordance withone embodiment.

FIG. 4 illustrates a flow block diagram of a method for managingphysical layer usage for communication between an external device and animplantable medical device in accordance with one embodiment.

FIG. 5 thus illustrates a flow block diagram of a method for managingselection of the physical layer during a communication session betweenan external device and an IMD in accordance with one embodiment.

DETAILED DESCRIPTION

It will be readily understood that the components of the embodiments asgenerally described and illustrated in the Figures herein, may bearranged and designed in a wide variety of different configurations inaddition to the described example embodiments. Thus, the following moredetailed description of the example embodiments, as represented in theFigures, is not intended to limit the scope of the embodiments, asclaimed, but is merely representative of example embodiments.

Reference throughout this specification to “one embodiment” or “anembodiment” (or the like) means that a particular feature, structure, orcharacteristic described in connection with the embodiment is includedin at least one embodiment. Thus, appearances of the phrases “in oneembodiment” or “in an embodiment” or the like in various placesthroughout this specification are not necessarily all referring to thesame embodiment.

The terms “small”, “smaller”, “large”, and “larger”, are used herein inconnection with payload to refer to relative size to one another, andnot to refer to a specific amount of data. For example, a first payloadthat is “smaller” as compared to a second payload, simply indicates thatthe first payload has less data than in the second payload.

The term “actual telemetry break”, as used herein, refers to a conditionin which a communications link has at least temporarily ended due to oneor more of return errors and/or bad packets received by an IMD.

The term “potential telemetry break”, as used herein, refers to acondition in which a communications link is maintained, but experiencesa number of return errors and/or bad packets received by an IMD inexcess of a threshold, thereby indicating a high likelihood that thecommunications link is about to end.

The term “telemetry break condition”, as used herein, refers to acondition of a communications link with respect to an actual orpotential telemetry break. A telemetry break condition represents oneexample of connection criteria.

The terms “low power” and “high power”, as used herein, do not refer toabsolute power levels, but instead referred to power levels relative toone another.

The term “connection criteria” refers to at least one of data throughputrequirement, communication type, a battery indicator, a telemetry breakcondition or link condition of the communications link between the IMDand ED.

In accordance with new and unique aspects herein, methods and systemshave been developed to take advantage of the availability of multiplephysical layers (PHYs), such as the additions to the PHYs offered in theBluetooth 5.0 and higher versions, in connection with improvingtransmission efficiency, limiting power usage and the like. The PHYrepresents the bottom layer of the protocol stack. Bluetooth 5.0 andlater versions add two new PHY variance (LE 2 M and LE coded) ascompared to the single PHY variant offered in Bluetooth 4.2 and earlierversions (LE 1 M). The LE 2 M PHY allows the physical layer to operateat a rate of 2 million symbols per second (2 Ms/s), thereby enabling ahigher data rate, as compared to the Bluetooth version 4.2 PHY of LE 1 M(having a data rate of 1 million symbols per second). The terms “bitsper second”, “b/s”, “symbols per second”, and “s/s”, are usedinterchangeably with one another throughout, although it is recognizedthat a symbol may not be limited to a single bit, but instead may bedefined by a known number of bits. The LE 2 M PHY doubles the symbolrate relative to the LE 1 M PHY. The LE 1 M PHY uses two level Gaussianfrequency shift keying (GFSK) with a binary zero represented by adecrease in the carrier frequency by a given frequency deviation (185kHz) and a binary one represented by increasing the carrier frequency bythe same deviation (185 kHz). The LE 2 M PHY uses two level GFSK with abinary zero represented by a decrease in the carrier frequency by agiven frequency deviation (370 kHz) and a binary one represented byincreasing the carrier frequency by the same deviation (370 kHz).

The LE coded PHY allows the communication range to be greatly increased,such as potentially quadrupled, as compared to the range afforded by theLE 1 M PHY in accordance with the Bluetooth 4.2 version (all otherfactors and the environment being equal). The increased range of the LEcoded PHY is achieved without increasing the transmission powerrequired, through the use of forward error correction (FEC). However,the added error correction capability afforded in the LE coded PHYsacrifices data rate. More specifically, the LE 1 M PHY and LE 2 M PHYutilize error detection, such as a cyclic redundancy check (CRC), inwhich a CRC value is calculated for data packets by the transmitter andappended to the packet. The receiver recalculates the CRC and comparesthe recalculated value with the value appended to the packet. When thevalues are not the same, an error is declared. When an error isdetected, the receiver requests or “hints” (e.g., by failing toacknowledge receipt of a packet at the link layer) that the transmitterresend the data packet. When a transceiver receives a request for datato be resent, or when a transceiver does not receive an acknowledgment,the transceiver resends the data packet.

The LE coded PHY adds advanced error correction that enables thereceiver to not need the data to be retransmitted, but instead allowsthe receiving device to perform error “correction” (not simply error“detection” as in Bluetooth version 4.2). The forward error correctionadds additional redundant bits to transmitted packets, where theredundant bits are intended to support application of the FEC algorithmand to determine the correct value for received bits. By way of example,the FEC encoding may utilize a convolution encoder which generatesS-bits for each input bit using a predetermined generator polynomial.Different coding schemes may be utilized, such as a 2-bit (S=2) or an8-bit (S=8). In a 2-bit encoding scheme, the convolution encoder outputs2 bits for each single input bit. In a 8-bit encoding scheme, theconvolution encoder outputs 8-bits for each single input bit. A patternmapper converts each bit from the convolution FEC encoder into P symbolswhere the value of P depends on the coding scheme. When a 2-bit codingscheme is used P=1, when an 8-bit coding scheme is utilized, P=4. Thedifferent coding schemes affect transmission range, with the LE Coded 2Sscheme PHY having a range that is approximately double the range of theLE 1 M PHY, while the range corresponding to the LE coded 8S scheme PHYis approximately four times greater than the range afforded by the LE 1M PHY. However, the data rate associated with the LE coded 8S schemedrops to 125 kb per second (125 Ks/s), and the data rate associated withLE coded 2S scheme drops to 500 kb per second (500 Ks/s), as compared tothe 1 Mb per second (1 Ms/s) data rate of the LE 1 M PHY.

In accordance with new and unique aspects herein, methods and systemsare described that actively switch to different physical layers (PHY)and corresponding data rates depending upon a type of communicationand/or an amount of data to be transferred during the communicationsession. Embodiments herein seek to maximize the nature of the threedifferent physical layers: LE 1 M, LE 2 M, and LE Coded. LE 1 M is themost common PHY and is compatible with all Bluetooth transceivers. LE 1M can only support the 1 Mb/s data rate and does not support any errorcorrections. LE 2 M can support heavier data transfer loads of 2 Mb/s.LE Coded can support lower data rates such as 125 Kb/s and 500 Kb/s. LECoded can also use forward error correction to recover erroneous datapackets to improve the fidelity of the signal reception. In order to useLE 2 M or LE Coded PHYs, both an IMD and an external device must usetransceivers that are compliant to the Bluetooth 5.0 standard.

Table 1 below shows a comparison of the effects upon performance whenusing different PHY and data rates. Performance may be defined invarious manners, such as based on bit error rate, signal to noise ratio,dropped connections, number of data packets that are not properlyreceived, and the like. At the lower data rates, when using the LE CodedPHY, significant improvements can be seen regarding communicationdistance and current savings while maintaining a constant performance.The LE 1 M PHY serves as a baseline as it is the current setting forconventional IMDs. Using a 2 Mb/s data rate will allow larger amounts ofdata to be transferred faster at the cost of shorter communication rangeand more power consumption. The lower data rates provide significantimprovements in communication distance and power consumption.

TABLE 1 TABLE OF PERFORMANCE VS. DATA RATE AND PHY Data Loss/GainCurrent PHY Rate (dB) Distance Consumption LE 2M 2 Mb/s −3.1  0.7 × D−29%  LE 1M 1 Mb/s 0 D  0% LE Coded 500 Kb/s +4.4 1.66 × D 29% 2S LECoded 125 Kb/s +7.0 2.24 × D 40% 8S

Table 1 illustrates differences in loss/gain (in dB), distance andcurrent consumption in connection with each PHY and data rate relativeto reference levels associated with the LE 1 M PHY. The loss/gain columnrepresents an amount that the transceiver will need to increase ordecrease the gain, relative to a reference level, to afford a sameperformance level as the reference LE 1 M PHY. As shown in Table 1, inorder to maintain a same level of performance as the LE 1 M PHY, whenthe PHY is switched to the LE 2 M PHY, (e.g., with all other factorsremaining equal such as distance, interference, overall environment),the transceiver gain needs to be increased by 3.1 dB. In other words,when an IMD switches from the LE 1 M PHY to the LE 2 M PHY, the IMDwould need to increase the transmit/receive gain by 3.1 dB to maintain acommon communication link quality at a given distance D relative to thetransmit/receive gain that the transceiver was utilizing whencommunicating over the LE 1 M PHY. The increase of 3.1 dB of gain causesan increase in current consumption by the IMD of approximately 29% ascompared to the current consumption of the IMD when utilizing the LE 1 MPHY.

Conversely, when switching from the LE 1 M PHY to the LE Coded 2S or LECoded 8S PHY, if all other factors are maintained constant, thetransceiver gain could be decreased by 4.4 dB and 7.0 dB, respectively,(below the gain setting utilized by the LE 1 M PHY) to maintain a commoncommunication link quality at a given distance D relative to thetransmit/receive gain when communicating utilizing the LE 1 M PHY. Thedecreases of 4.4 dB and 7.0 dB of gain results in lower currentconsumption by the IMD (when utilizing the LE Coded 2S or LE Coded 8SPHY) of approximately 29% and 40%, respectively, as compared to thecurrent consumption of the IMD when utilizing the LE 1 M PHY.

Alternatively, if the IMD maintains the transmit/receivegain/sensitivity constant when switching from the LE 1 M to the LE 2 MPHY, the IMD will exhibit a same performance, when utilizing the LE 2 MPHY at a shorter communications distance, namely at distance of 0.7Drelative to the reference distance (D) associated with the LE 1 M PHY.Conversely, when switching from the LE 1 M PHY to the LE Coded 2S or LECoded 8S PHY, if all other factors are maintained constant, when the IMDutilizes the LE Coded 2S or LE Coded 8S PHY, the IMD will exhibit a sameperformance, as when using the LE 1 M PHY, at greater communicationsdistances of 1.66D and 2.44D, respectively.

FIG. 1 illustrates a simplified block diagram of a system operated inaccordance with embodiments herein. The system includes one or more IMD101 and one or more external device (ED) 201 (e.g., table computer,smart phone, smart watch, laptop, and/or the like) that are configuredto communicate with one another wirelessly over a communications link.

The IMD 101 is implanted within a patient (e.g., proximate to and/orwithin a heart, proximate to the spinal cord). Embodiments may beimplemented in connection with one or more implantable medical devices(IMDs). Non-limiting examples of IMDs include one or more ofneurostimulator devices, implantable leadless monitoring and/or therapydevices, and/or alternative implantable medical devices. For example,the IMD may represent a cardiac monitoring device, pacemaker,cardioverter, cardiac rhythm management device, defibrillator,neurostimulator, leadless monitoring device, leadless pacemaker and thelike. The IMD may measure electrical and/or mechanical information. Forexample, the IMD may include one or more structural and/or functionalaspects of the device(s) described in U.S. Pat. No. 9,333,351, entitled“NEUROSTIMULATION METHOD AND SYSTEM TO TREAT APNEA” issued May 10, 2016and U.S. Pat. No. 9,044,610, entitled “SYSTEM AND METHODS FOR PROVIDINGA DISTRIBUTED VIRTUAL STIMULATION CATHODE FOR USE WITH AN IMPLANTABLENEUROSTIMULATION SYSTEM” issued Jun. 2, 2015, which are herebyincorporated by reference. The IMD may monitor transthoracic impedance,such as implemented by the CorVue algorithm offered by St. Jude Medical.Additionally or alternatively, the IMD may include one or morestructural and/or functional aspects of the device(s) described in U.S.Pat. No. 9,216,285, entitled “LEADLESS IMPLANTABLE MEDICAL DEVICE HAVINGREMOVABLE AND FIXED COMPONENTS” issued Dec. 22, 2015 and U.S. Pat. No.8,831,747, entitled “LEADLESS NEUROSTIMULATION DEVICE AND METHODINCLUDING THE SAME” issued Sep. 9, 2014, which are hereby incorporatedby reference. Additionally or alternatively, the IMD may include one ormore structural and/or functional aspects of the device(s) described inU.S. Pat. No. 8,391,980, entitled “METHOD AND SYSTEM FOR IDENTIFYING APOTENTIAL LEAD FAILURE IN AN IMPLANTABLE MEDICAL DEVICE” issued Mar. 5,2013 and U.S. Pat. No. 9,232,485, entitled “SYSTEM AND METHOD FORSELECTIVELY COMMUNICATING WITH AN IMPLANTABLE MEDICAL DEVICE” issuedJan. 5, 2016, which are hereby incorporated by reference. Additionallyor alternatively, the IMD may be a subcutaneous IMD that includes one ormore structural and/or functional aspects of the device(s) described inU.S. application Ser. No. 15/973,195, entitled “SUBCUTANEOUSIMPLANTATION MEDICAL DEVICE WITH MULTIPLE PARASTERNAL-ANTERIORELECTRODES” filed May 7, 2018; U.S. application Ser. No. 15/973,219,entitled “IMPLANTABLE MEDICAL SYSTEMS AND METHODS INCLUDING PULSEGENERATORS AND LEADS” filed May 7, 2018; U.S. application Ser. No.15/973,249, entitled “SINGLE SITE IMPLANTATION METHODS FOR MEDICALDEVICES HAVING MULTIPLE LEADS”, filed May 7, 2018, which are herebyincorporated by reference in their entireties. Further, one or morecombinations of IMDs may be utilized from the above incorporated patentsand applications in accordance with embodiments herein. Embodiments maybe implemented in connection with one or more subcutaneous implantablemedical devices (S-IMDs). For example, the S-IMD may include one or morestructural and/or functional aspects of the device(s) described in U.S.application Ser. No. 15/973,219, entitled “IMPLANTABLE MEDICAL SYSTEMSAND METHODS INCLUDING PULSE GENERATORS AND LEADS”, filed May 7, 2018;U.S. application Ser. No. 15/973,195, entitled “SUBCUTANEOUSIMPLANTATION MEDICAL DEVICE WITH MULTIPLE PARASTERNAL-ANTERIORELECTRODES”, filed May 7, 2018; which are hereby incorporated byreference in their entireties. The IMD may deliver some type oftherapy/treatment, provide mechanical circulatory support and/or merelymonitor one or more physiologic characteristics of interest (e.g., PAP,CA signals, impedance, heart sounds).

Additionally or alternatively, the IMD may be any of the implantabledevices described in U.S. application Ser. No. 16/930,791, titled“METHODS, DEVICES AND SYSTEMS FOR HOLISTIC INTEGRATED HEALTHCARE PATIENTMANAGEMENT”, filed Jul. 16, 2020, which is incorporated by reference inits entirety. As non-limiting examples, the IMD may be a body generatedanalyte or BGA test device which shall mean any and all equipment,devices, disposable products utilized to collect and analyze a BGA. Theterms “body generated analyte” and “BGA” shall have the meaning definesin the U.S. application Ser. No. 16/930,791. The BGA test device mayimplement one or more of the methods, devices and systems described inthe following publications, all of which are incorporated herein byreference in their entireties: U.S. Patent Publication Number2011/0256024, entitled “MODULAR ANALYTE MONITORING DEVICE”, publishedOct. 20, 2011; U.S. Patent Publication Number 2010/0198142, entitled“MULTIFUNCTION ANALYTE TEST DEVICE AND METHODS THEREFORE”, publishedAug. 5, 2010; U.S. Patent Publication Number 2011/0160544, entitled“SYSTEM AND METHOD FOR ANALYSIS OF MEDICAL DATA TO ENCOURAGE HEALTHCAREMANAGEMENT”, published Jun. 30, 2011; U.S. Pat. No. 5,294,404, entitled“REAGENT PACK FOR IMMUNOASSAYS” issued Mar. 15, 1994; U.S. Pat. No.5,063,081, entitled “METHOD OF MANUFACTURING A PLURALITY OF UNIFORMMICROFABRICATED SENSING DEVICES HAVING AN IMMOBILIZED LIGAND RECEPTOR”issued Nov. 5, 1991; U.S. Pat. No. 7,419,821, entitled “APPARATUS ANDMETHODS FOR ANALYTE MEASUREMENT AND IMMUNOASSAY” issued Sep. 2, 2008;U.S. Patent Publication Number 2004/0018577, entitled “MULTIPLE HYBRIDIMMUNOASSAYS” published Jan. 29, 2004; U.S. Pat. No. 7,682,833, entitled“IMMUNOASSAY DEVICE WITH IMPROVED SAMPLE CLOSURE” issued Mar. 23, 2010;U.S. Pat. No. 7,723,099, entitled “IMMUNOASSAY DEVICE WITHIMMUNO-REFERENCE ELECTRODE” issued May 25, 2010; and Baj-Rossi et al.“FABRICATION AND PACKAGING OF A FULLY IMPLANTABLE BIOSENSOR ARRAY”,(2013) IEEE, pages 166-169, all of which are incorporated by referencein their entireties.

The determination of which physical layer and data rate to be utilizedmay be initiated when the transceiver of the IMD 101 sends outadvertisement packets and/or at any point during a communicationssession. The advertisement packets may include information such as theBLE Standard (e.g., Bluetooth 4.0, 4.2, 5.0) supported by the IMD,compatible PHY types (LE 1 M, LE 2 M, LE Coded), a type of communicationto occur (e.g., alert, command, software update, data transfer, etc.),and size of the data to be transferred. When the external device 201(e.g., programmer, bedside monitor, smartphone, etc.) receives theadvertisement packet, the external device 201 will determine based onthe encoded information how best to connect to the IMD 101. Once theexternal device 201 knows the IMD transceiver capabilities, the externaldevice 201 can control the transceiver parameters both at the initialconnection state and throughout the communication session in order toprovide a desired (e.g., optimal) RF performance. Once a communicationsession is initiated, the ED 201 is afforded the ability to change thePHY and data rate dynamically to adjust for circumstances such aschanges in distance between the IMD 101 and ED 201, changes inorientation of the patient (and IMD 101) relative to the ED 201, changesin interference and the like.

FIG. 2A illustrates a block diagram of communication circuitry 200utilized in accordance with an embodiments herein. The componentsdescribed herein can include or represent hardware and softwareinstructions (e.g., software stored on a tangible and non-transitorycomputer readable storage medium, such as a computer hard drive, ROM,RAM, or the like) that perform the operations described herein. Thehardware may include electronic circuits that include and/or areconnected to one or more logic-based devices, such as microprocessors,processors, controllers, or the like. Additionally or alternatively, thecomponents may be hard-wired logic circuits.

The communication circuitry 200 is within an IMD and optionally withinone or more external device. The communication circuitry 200 isconfigured to establish and maintain the communication link between theIMD 101 and external devices. In one example, the communicationcircuitry 200 may be configured to handle and/or manage thebi-directional communication link between the IMD 101 and the ED 201. Inone example, the communication circuitry 200 is an RF circuit. Inanother example, the communication circuitry 200 includes a transponderthat transmits signals and a receiver that receives signals. In yetanother example, the communication circuitry 200 includes a transceiver212 (TX/RX) that both transmits signals and receives signals.Specifically, a transceiver includes both a transponder and a receiver.As explained herein, the communication circuitry 200 transmits, amongother things, advertisement notices, connection requests, connectionresponses, scan requests, scan responses, data packets and the like. Thetransceiver 212 is tuned to communicate with external devices, includingthe ED 201 over one or more frequency bands and in accordance with acorresponding protocol. The transceiver 212 may include one or moretransmitters/transponders, receivers, and/or transceivers. Optionally,the communication circuitry 200 may be electrically coupled to anantenna (not shown). For example, an antenna may be provided within aheader of an IMD as one example. As another example, electrodes on orcoupled to the IMD may be utilized to convey the wireless communicationsignals. The communication circuitry 200 also scans for connectionrequest data packets from external devices. In one example the externaldevice is the ED 201 of FIG. 1.

The communication circuitry 200 also includes one or more processors 214including a communication control processor 215, a local memory 216, andtelemetry circuitry 218, all of which may be implemented on a commoncircuit board, within a common subsystem or within a common integratedcircuit. Specifically, the communication circuitry 200 is incommunication with other circuits, components, and modules of the IMD101 including controller circuit, and local memory 216. Thecommunication control processor 215 may support one or more wirelesscommunication protocols while communicating with an external device suchas the ED 201, such as Bluetooth low energy, Bluetooth, Medical ImplantCommunication Service (MICS), and/or the like.

The memory 216 stores instructions implemented by the communicationcontrol processor 215. Protocol firmware may be stored in memory 216,which is accessed by the communication control processor 215. Theprotocol firmware provides the wireless protocol syntax for thecommunication control processor 215 to assemble data packets,advertisement notices, connection request data packets, connectionresponses, establish communication links, such as communication, and/orpartition data received from an external device, such as ED 201.

The telemetry circuitry 218 in one example monitors the quality of thetelemetry or communications link. Alternatively, the telemetry softwareis stored in the memory that provides instructions that are followed bythe communication control processor or one or more of the processors 214related to the communication circuitry 200. The telemetry circuitry 218in one example determines when the link, and/or how often the link dropscausing interruptions in communications being passed through thecommunications link. In another example the telemetry circuitry 218determines the number of return errors received, number of bad packetsreceived, or the like. Optionally, the telemetry circuitry 218 tracksthe signal to noise ratio (RSSI) of the communication link. When thecommunication link is down or not working the telemetry circuitry 218verifies the power setting of the telemetry link and increases the powersetting when a break in the link occurs, or when a link is unable to beestablished. In this manner, the telemetry circuitry 218 facilitatesre-establishment of the link to assist in completing communicationsessions. Thus, the telemetry circuitry 218 not only makesdeterminations regarding when communication breaks occurs includingtiming to reestablish the link and the like, but additionally, thequality of the telemetry link is determined through various methodsincluding RSSI. The telemetry circuitry 218 also actively corrects anybreaks or poor quality communications by increasing power to establishand maintain the link.

FIG. 2B illustrates a full protocol stack structure of a Bluetoothprotocol. The top layer corresponds to various applications thatinteract with and utilize Bluetooth wireless communication. The hostmaintains various information, such as the generic access profile (GAP),generic attribute protocol (GATT), secure manager (SMP), attributeprotocol (ATT), and logical Link control and adaptation protocol(L2CAP). The controller implements, among other things, the link layer(LL) and the physical layer (PHY).

Returning to FIG. 2A, the communications circuitry 200 is configured toimplement the Bluetooth low energy protocol of FIG. 2B, including themultiple physical layers discussed herein. As explained herein, thecommunications circuitry 200 is configured to support bidirectionalcommunications utilizing a selected one of the LE 1 M, LE 2 M, LE Codedphysical layers (including the LE Coded 2S and LE Coded 8S). Optionally,during a communications session, the communications circuitry 200 maytransmit utilizing a first PHY and receive utilizing a second PHY. Forexample, during a communications session in which the IMD is downloadinga new firmware version, the IMD may receive data utilizing the LE 2 MPHY, while utilizing one of the LE Coded PHY to transmit to the ED. Asanother example, during a communication session in which the IMD isuploading stored EGM signals, the IMD may utilize the LE 2 M PHY totransmit the EGM signals to the ED, but utilize one of the LE Coded PHYto receive commands from the ED.

As explained herein, the communications circuitry 200 is configured tocommunicate wirelessly, with an external device (ED), utilizing aprotocol that utilizes multiple physical layers. The communicationscircuitry 200 is configured to transmit information indicating that thetransceiver is configured with first, second and third physical layers(PHYs) for wireless communication. The IMD further comprises memory 216configured to store program instructions and one or more processors 214configured to execute instructions to: obtain an instruction designatingone of the first, second and third PHY to be utilized for at least oneof transmission or reception, during a communication session, with theexternal device; and manage the transceiver 212 to utilize, during thecommunication session, the one of the first, second and third PHY asdesignated.

For example, the transceiver 212 is configured to transmit acommunications packet represents at least one of an advertisementpacket, a scan request packet or a scan response packet, thecommunications packet including the information indicating that thetransceiver is configured with the first, second and third PHYs.Additionally or alternatively, the transceiver 212 is configured toreceive an ED communications packet from the external device, the EDcommunications packet including the instruction designating the one ofthe first, second and third PHY. Additionally or alternatively, the oneor more processors 214 are configured to at least one of 1) determinethe type of communication or 2) determine a size of data set (alsoreferred to as a data throughput requirement) to be transferred betweenthe ED and IMD, the one or more processors 214 configured to generatethe instruction designating the one of the first, second and third PHYsbased on at least one of the type of communication or the size of thedata set.

In accordance with embodiments herein, when the protocol corresponds toa Bluetooth protocol, the first, second and third PHY corresponding toLE 1 M, LE 2 M and LE Coded PHYs, respectively, and the instructiondesignates the LE 2 M PHY when the type of communication corresponds toa large payload communication. The instruction designates the LE CodedPHY when the type of communication corresponds to a small payloadcommunication. The one or more processors are configured to manage areceiver of the transceiver to utilize the first PHY in connection withreceiving communications packets from the ED and to manage a transmitterof the transceiver to utilize the second PHY in connection withtransmitting communications packets to the ED.

In accordance with embodiments herein, the ED is also configured towirelessly communicate with the IMD utilizing a protocol that supportsmultiple physical layers (PHYs). The ED comprises an externaltransceiver configured to wirelessly communicate with the IMD; theexternal transceiver configured to receive a communications packet;memory configured to store program instructions; and one or moreprocessors that are configured, when implementing the programinstructions, to: analyze the communications packet for informationindicating whether the IMD is configured with multiple physical layers(PHYs) for wireless communication; select one of the multiple PHYs basedon at least one of a type of communication to occur, or a size of a dataset to be transferred, during the communication session; and transmit aninstruction to the IMD to utilize the one of the multiple PHYs selectedfor at least one of transmission or reception during the communicationsession.

Additionally or alternatively, the one or more processors are furtherconfigured to receive, as the communications packet, an advertisementpacket, and analyze a content of the advertisement packet for theinformation indicating where the IMD is configured with the multiplePHYs. Additionally or alternatively, the information analyzed from thecommunications packet indicates whether the IMD is compatible withBluetooth version 5.0 or higher. Additionally or alternatively, the oneor more processors are configured to determine the type of communicationand select between first or second PHY based on the type ofcommunication. Additionally or alternatively, the one or more processorsare configured to determine the size of the data set to be transferredand select between the second PHY or a third PHY based on the size ofthe data set to be transferred. Additionally or alternatively, followingthe select and transmit operations, the one or more processors areconfigured to manage the device transceiver to establish a communicationsession with the IMD utilizing the one of the multiple PHYs.

FIG. 3 illustrates a distributed processing system 300 in accordancewith one embodiment. In one example, the distributed processing system300 includes and implements the communication circuitry 200 as providedin FIG. 2A in one or more of the devices shown in FIG. 3. Thedistributed processing system 300 includes a server 302 connected to adatabase 304, a programmer 306, a local RF transceiver 308 and a userworkstation 310 electrically connected to a communication system 312.Any of the processor-based components in FIG. 3 (e.g., workstation 310,cell phone 314, PDA 316, server 302, programmer 306, IMD 101) maycommunicate with an IMD 317 that in one example is IMD 101 of FIG. 1. Inone example, the local RF transceiver 308 is the transceiver of 212 ofFIG. 2A. The various components illustrated in FIG. 3 are configured tocommunicate over a common wireless protocol, such as the Bluetooth lowenergy protocol. The components may implement various versions of theBLE protocol. For example, a subset of the IMDs 317 may implement aversion 4.0 or lower version of the BLE protocol (e.g., having only theLE 1 M PHY), while another subset of the IMD 317 may implement a version5.0 or higher version of the BLE protocol (e.g., having multiple PHYs).The cell phone 314 and programmer 306 may include transceivers thatsupport multiple PHYs (e.g., LE 1 M, LE2 M, LE coded), while the localPDA 316 only supports the LE 1 M PHY.

Various components within the system 300 may determine which PHY toutilize during communication, including but not limited to, the IMD 317,cell phone 314, local PDA 316, transceiver 308, programmer 306 andserver 302. For example, the programmer 306 and/or cell phone 314 mayinitially determine which physical layer to utilize during acommunication session. Additionally or alternatively, an IMD 317, withwhich the cell phone 314 and/or programmer 306 communicate, may make theinitial determination of the physical layer. Additionally oralternatively, the IMD 317 may determine that the initial physical layerdesignator for communication is not affording a sufficient level ofperformance or signal quality and instruct the cell phone 314,programmer 306 or other external device to switch to a more reliablephysical layer (e.g., switching from the LE 2 M layer to the LE 1 M orLE Coded layer).

The communication system 312 may be the internet, a voice over IP (VoIP)gateway, a local plain old telephone service (POTS) such as a publicswitched telephone network (PSTN), a cellular phone based network, andthe like. Alternatively, the communication system 312 may be a localarea network (LAN), a campus area network (CAN), a metropolitan areanetwork (MAN), or a wide area network (WAN). The communication system312 serves to provide a network that facilitates the transfer/receipt ofinformation such as cardiac signal waveforms, ventricular and atrialheart rates.

The server 302 is a computer system that provides services to othercomputing systems over a computer network. The server 302 interfaceswith the communication system 312 to transfer information between theprogrammer 306, the local RF transceiver 308, the user workstation 310as well as a cell phone 314, a personal data assistant (PDA) 316, andIMD 317 to the database 304 for storage/retrieval of records ofinformation. On the other hand, the server 302 may upload raw cardiacsignals from an implanted lead 322, surface ECG unit 320 or the IMD 317via the local RF transceiver 308 or the programmer 306.

The database 304 stores information such as cardiac signal waveforms,ventricular and atrial heart rates, thresholds, and the like, for asingle or multiple patients. The information is downloaded into thedatabase 304 via the server 302 or, alternatively, the information isuploaded to the server from the database 304. The programmer 306 issimilar to an external device or instrument and may reside in apatient's home, a hospital, or a physician's office. The programmer 306interfaces with the lead 322 and the IMD 317. The programmer 306 maywirelessly communicate with the IMD 317 and utilize protocols, such asBluetooth, GSM, infrared wireless LANs, HIPERLAN, 3G, satellite,inductive as well as circuit and packet data protocols, and the like.Alternatively, a hard-wired connection may be used to connect theprogrammer 306 to the IMD 317. The programmer 306 is able to acquirecardiac signals from the surface of a person (e.g., ECGs), intra-cardiacelectrogram (e.g., IEGM) signals from the IMD 317, and/or cardiac signalwaveforms, ventricular and atrial heart rates, and detection thresholdsfrom the IMD 317. The programmer 306 interfaces with the communicationsystem 312, either via the internet or via POTS, to upload theinformation acquired from the surface ECG unit 320, the lead 322 or theIMD 317 to the server 302.

The local RF transceiver 308 interfaces with the communication system312 to transmit and receive telemetry data and information beingtransmitted to and from the RF transceiver 308. In one example thecommunication system monitors the communication link and recordstelemetry breaks, length of breaks, number of breaks in a giveninterval, time to reestablish a signal, signal to noise ratio, and thelike. In this manner the communication system 312 provides with a userthe quality and/or strength of a communication signal and amount orstrength of local interference. In addition, the communication system312 (e.g., server 302, cell phone 314, work station 310, programmer 306)may, based on the monitored communication quality, increase or decreasethe power of a signal being transmitted. In one example, thecommunication system 312 monitors both advertising channels andconnection channels, thus providing advertising data packets through andcommunicating through the advertising channels with external devices.Similarly, the communication system 312 is able to provide acommunication pathway through a connection channel.

The user workstation 310 may interface with the communication system 312to download cardiac signal waveforms, ventricular and atrial heartrates, and detection thresholds via the server 302 from the database304. Alternatively, the user workstation 310 may download raw data fromthe surface ECG units 320, lead 322 or IMD 317 via either the programmer306 or the local RF transceiver 308 or cell phone 314 or PDA 316. Oncethe user workstation 310 has downloaded the cardiac signal waveforms,ventricular and atrial heart rates, or detection thresholds, the userworkstation 310 may process the information in accordance with one ormore of the operations described above. The user workstation 310 maydownload the information and notifications to the cell phone 314, thePDA 316, the local RF transceiver 308, the programmer 306, or to theserver 302 to be stored on the database 304.

Process for Managing a Physical Layer Utilized for Communication

FIG. 4 illustrates a flow block diagram of a method for managingphysical layer usage for communication between an external device and animplantable medical device. The method may be implemented by hardwarecomponents, software components, and/or a combination of hardwarecomponents and software components working together to implement themethod. The following description will be provided in the context of anexternal device acting as a host by receiving an advertisement andmaking the various determinations to select the PHY to be utilized.Although, it is understood that in certain instances, the IMD may serveas the host, and in other instances, a remote server may serve as thehost when directly or indirectly communicating with an IMD.

At 402, one or more processors of the host (e.g., external device)receive a communications packet transmitted by the slave (e.g., IMD).For example, the communications packet may represent at least one of anadvertisement packet, a connect request packet, a connect responsepacket, a scan request packet, a scan response packet, and the like. Thecommunications packet includes information indicating whether thetransceiver of the IMD is configured with the first, second and thirdPHYs. Additionally or alternatively, the transceiver is configured toreceive an ED communications packet from the external device, the EDcommunications packet including the instruction designating the one ofthe first, second and third PHY. Additionally or alternatively, the oneor more processors are configured to at least one of 1) determine thetype of communication or 2) determine a size of data set (datathroughput requirement) to be transferred between the ED and IMD, theone or more processors configured to generate the instructiondesignating the one of the first, second and third PHY's based on atleast one of the type of communication or the size of the data set.

At 404, the one or more processors of the host analyze the advertisementnotice to determine certain information about the IMD. Among otherthings, the host/master determines communications capability informationabout the IMD, such as which Bluetooth standard is supported by the IMD(e.g., Bluetooth 4.0, 4.2, 5.0), compatible PHY types supported by theIMD (e.g., LE 1 M, LE2 M, LE coded) and the like. When the IMD isdetermined to support Bluetooth 5.0 or above versions and/or determinedto be compatible with PHY types of LE 2 M and LE coded, flow moves to412. Otherwise, flow moves to 406.

At 406, the one or more processors of the host set the PHY to beutilized during the transmit and receive operations to a first PHY thatmay represent the only PHY type supported by the IMD (e.g., the LE 1 MPHY). At 408, the transceiver of the host changes to the first PHY leveland the corresponding data rate. In the present example, the transceiverswitches to maintain a data rate of 1 Mb/s.

At 410, the host and the slave exchange additional information toestablish a communications session. The operations at 406-410 may beimplemented utilizing the PHY Update Procedure, as described in Section5.1.10 the Bluetooth Specification Version 5.0, volume 6, part B. The“capitalize” field names described herein shall have the meanings setforth in the Bluetooth Specification version 5.0, volume 6. TheBluetooth specification Version 5.0, volume 6 is expressly incorporatedherein by reference in its entirety. The PHY update procedure may beinitiated either upon request by the host or autonomously by the linklayer of the slave. Either the master or slave (e.g., external device orIMD) may initiate the PHY update procedure at any time after enteringthe connection state. The link layer PHY preferences may change during aconnection or between connections and therefore, are not necessarilycached by peer devices. When the PHY update procedure is initiated bythe host/master (e.g., external device), the host/master sends anLL_PHY_REQ PDU (link layer PHY request protocol data unit). Theslave/IMD responds with an LL_PHY_UPDATE_IND PDU (LL PHY updateindication PDU).

Alternatively, when the PHY update procedure is initiated by theslave/IMD, the IMD sends an LL_PHY_REQ PDU, in response to which themaster/ED responds with an LL_PHY_UPDATE_IND PDU. The TX_PHYS (transmitphysical later) and RX_PHYS (receive PHY) fields of the LL_PHY_REQ andLL_PHY_RSP PDUs shall be used to indicate the PHYs that the sending linklayer prefers to use. If the sender wants a symmetric connection (e.g.,one where the two PHYs are the same), the sender should make both fieldsthe same, only specifying a single PHY. The M_TO_S_PHY (Master to slavephysical layer) and the S_TO_M_PHY (slave to master physical layer)fields of the LL_PHY_UPDATE_IND PDU shall indicate the PHYs that shouldbe used after the incident. If the master initiates the PHY updateprocedure, the master shall determine the PHY to use in each directionbased on the contents of the LL_PHY_REQ and LL_PHY_RSP protocol dataunits (PDUs) using the following rules: 1) the M_TO_S_PHY field of theLL_PHY_UPDATE_IND PDU shall be determined from the master's TX_PHYSfield and the slave's RX_PHYS field; 2) the S_TO_M_PHY field of theLL_PHY_UPDATE_IND PDU shall be determined from the master's RX_PHYSfield and the slave's TX_PHYS field. In each of the foregoing cases, thefollowing rules apply: 1) if, for at least one PHY, the correspondingbit is set to 1 in both the TX_PHYS and RX_PHYS fields, the master shallselect any one of those PHYs for that direction; 2) if there is no PHYfor which the corresponding bit is set to 1 in both the TX_PHYS andRX_PHYS fields, the master shall not change the PHY for that direction.

If the slave initiates the PHY update procedure, the master shalldetermine the PHY to use in each direction based on the contents of theLL_PHY_REQ PDU sent by the slave using the following rules: 1) theM_TOS_PHY field of the LL_PHY_UPDATE_IND PDU shall be determined fromthe RX_PHYS field of the slave's PDU; 2) the S_TO_M_PHY field of theLL_PHY_UPDATE_IND PDU shall be determined from the TX_PHYS field of theslave's PDU. In each of the foregoing cases the following rulesapply: 1) if, for at least one PHY, the PHY is one that the masterprefers to use and the corresponding bit is set to 1 in the relevantfield of the slave's PDU, the master shall select any one of those PHYsfor that direction; 2) if there is no PHY which the master prefers touse and for which the corresponding bit is set to 1 in the relevantfield of the slave's PDU, the master shall not change the PHY for thatdirection.

The following discussion shall apply irrespective of which deviceinitiated the PHY update procedure. Irrespective of the above rules, themaster may leave both directions unchanged. If the slave specified asingle PHY in both the TX_PHYS and RX_PHYS fields and both fields arethe same, the master shall either select the PHY specified by the slavefor both directions or shall leave both directions unchanged. Bothdevices shall use the new PHYs starting at the instant. If a master orslave sends an LL_PHY_REQ PDU to a device that does not understand thatPDU, then the receiving device shall send an LL_UNKNOWN_RSP PDU inresponse. The procedure has completed when: 1) an LL_UNKNOWN_RSP orLL_REJECT_EXT_IND PDU has been sent or received; 2) an LL_PHY_UPDATE_INDPDU indicating that neither PHY will change has been sent or received;or 3) the master sends an LL_PHY_UPDATE_IND PDU indicating that at leastone PHY will change and the instant has been reached. In this case, theprocedure response timeout shall be stopped on the master when it sendsthat PDU and on the slave when it receives that PDU. The controllershall notify the host of the PHYs now in effect when the PHY UpdateProcedure completes if either it has resulted in a change of one or bothPHYs or if the procedure was initiated by a request from the Host.Otherwise, it shall not notify the host that the procedure took place.

Returning to 404, when flow moves to 412, the one or more processors ofthe host determine the type of communication to occur. Nonlimitingexamples of communication types may include alert communications,command communications, software updates, data transfers and the like.Alert and command type communications include relatively small amountsof information, also referred to as a small or smaller payloadcommunications, such as when an IMD is conveying an alert to an externaldevice or when an external device may be downloading a command to directthe IMD to change an operation (e.g., switch to a different pacing mode,change one or more pacing parameters and the like). Software updatecommunications include a relatively large amount of information, alsoreferred to as large or larger payload communications, that isdownloaded to the IMD. For example, a software update (includingfirmware updates) may modify, add, or replace a therapy algorithm,detection algorithm, and the like. The large payload communications mayalso include data transfers, such as when uploading large amounts ofdata from the IMD to the external device. For example, a data transfermay involve transfer of EGM signals stored over a period of time, alongwith data markers and other analytics identified by the IMD.

At 414, the one or more processors of the host determine whether thecurrent communication type represents a small payload (e.g., an alert orcommand type communication) and if so, flow moves to 416. Otherwise,flow moves to 422.

At 416, the one or more processors of the host set the PHY to beutilized during the transmit and receive operations to a second PHY thatis deemed well-suited for the alert/command type communications. In thepresent example, the second PHY is set to correspond to the LE coded PHYand is set with S=8. At 418, the transceiver of the host changes to thesecond PHY and the corresponding data rate. In the present example, thetransceiver switches to maintain a data rate of 125 Kb/s at the LE codedS8 PHY.

At 420, the host and the slave exchange additional information toestablish a communications session. The operations at 416-420 mayinclude the exchange of the various PDU discussed above in connectionwith setting the PHY at 406, changing the data rate at 408 andestablishing a connection at 410.

Returning to 414, when flow moves to 422, the one or processors of thehost determine whether the type of communication corresponds to asoftware update, such as a firmware download. When the communicationcorresponds to a software update, flow branches to 424. Otherwise, flowcontinues to 430.

At 424, the one or more processors of the host set the PHY to beutilized during the transmit and receive operations to a third PHY thatis deemed well-suited for the software update type communications. Inthe present example, the third PHY is set to correspond to the LE 2 MPHY. At 426, the transceiver of the host changes to the third PHY andthe corresponding data rate. In the present example, the transceiverswitches to maintain a data rate of 2 Mb/s at the LE 2 M PHY. At 428,the host and the slave exchange additional information to establish acommunications session. The operations at 424-428 may include theexchange of the various PDU discussed above in connection with settingthe PHY at 406, changing the data rate at 408 and establishing aconnection at 410.

Returning to 422, when the flow moves to 430, the process has determinedthat the communication does not relate to an alert or command, nor asoftware update. Accordingly, the one or more processors of the hostdetermine the size of a data transfer to occur during the communication.

At 432, the one or more processors of the host determine whether thesize of the data transfer exceeds or falls below a threshold, and basedthereon flow branches to 424 or 434. For example, the communication maycorrespond to uploading ECG signals (saved in the IMD) to the externaldevice in combination with event markers and other analytics determinedby the IMD. When ECG signals and related markers/analytics are to beuploaded, the size of the data transfer is considered to be relativelylarge, and would exceed the threshold at 432, thereby directing flow to424. As noted above, at 424, the one or more processors utilize the LE 2M PHY and the data rate of 2 Mb per second. Alternatively, the size ofthe data transfer may be much smaller, such as when limited results ofECG analysis are to be uploaded. For example, an IMD may simply upload alevel of burden associated with an arrhythmia of interest, a batterylevel, and the like. When a smaller amount of data is to be transmitted,flow moves from 432 to 434. At 434, the one or more processors of thehost set the PHY to the third PHY, but set the encoding to a differentencoding level, such as the LE coded PHY while utilizing S2 encoding. At436, the transceiver of the host changes to the third PHY level and thecorresponding data rate. In the present example the transceiver switchesto maintain a data rate of 500 Kb/s. At 438, the host and the slaveexchange additional information to establish a communication session.The operations at 434-438 may include the exchange of the various PDUdiscussed above in connection with setting the PHY at 406, changing thedata rate at 408 and establishing a connection at 410.

As explained in accordance with the process of FIG. 4, when the externaldevice (e.g., programmer) first detects an advertisement notice from theIMD, the external device determines what version of the Bluetoothwireless communication standard is implemented by the IMD. If the IMDuses a transceiver configured in accordance with a Bluetooth standardless than 5.0, then the external device will establish a communicationsession with the IMD utilizing the single PHY associated with olderBluetooth standards, namely the LE 1 M PHY (as that is the only PHYsupported by the IMD). The LE 1 M PHY only supports a 1 Mb/s data ratefor connection. If, however, the IMD includes a transceiver configuredto utilize a Bluetooth 5.0 or above standard, then the next step is todetermine the purpose of the communication session. If an alert messageneeds to be sent from the IMD to the external device or a command needsto be sent from the external device to the IMD, the lowest data rate canbe applied as this type of transaction is not data heavy. The externaldevice will connect using the LE Coded 8S PHY with the data rate set to125 Kb/s. If a more substantial transmission such as a firmware downloador data transfer was needed, then the programmer would need to identifywhether a low data rate or high data rate should be used. For a firmwaredownload and a large data transfer, the highest data rate would be used.The external device would connect using LE 2 M PHY with 2 Mb/s datarate. Alternatively, if the amount of data transferred is relativelylow, then a lower data rate of 500 Kb/s with an LE Coded 2S PHY can beused.

It should be recognized that while the flowchart in FIG. 4 illustrateswhat an initial connection might look like, this process also allows forthe host to dynamically change the PHY and data rate settingsdynamically during a communication session. For example, the decisionsand branches of FIG. 4 may be applied during a communication session. Ifthe data payload is heavier than expected, the programmer can switch toa higher data rate to speed up the data transfer. Alternatively, if thecommunication session is suffering from interference or loss ofconnection, the programmer can switch to a lower data rate to strengthenthe connection at the cost of longer session duration. Lastly, ifbattery capacity is a constraint, lower data rates can be used to saveon current consumption.

FIG. 5 thus illustrates a flow block diagram of an alternative methodfor managing change of the physical layer during a communication sessionbetween an external device and an IMD. The method may be implemented byhardware components, software components, and/or a combination ofhardware components and software components working together toimplement the method.

At 502, one or more processors of the IMD and ED establish acommunications link, utilizing a desired physical layer that may bechosen in various manners. For example, the initial physical layer orcombination of layers may be chosen in accordance with the process ofFIG. 4. Alternatively, the initial physical layer may be predeterminedbased on prior communication sessions. For example, the external deviceand IMD may be preprogrammed to begin all communication sessions withthe physical layer available in the Bluetooth standard version 4.0(e.g., LE 1 M PHY).

At 504, one or more processors monitor connection criteria during thecurrent session, such as one or more of telemetry break condition, adata throughput requirement, a battery indicator, a communication typeor a link condition. In one example, the connection criteria correspondto a telemetry break condition that is an actual break wherecommunication is lost for a predetermined interval and must be restoredor reestablished. The predetermined interval may be a second, less thana second, more than a minute, and the like. In another example, thetelemetry break condition is a potential telemetry break. The potentialtelemetry break is determined based on measured parameters such assignal strength, interference noise level, signal to noise ratio, andthe like. In one example a threshold is provided related to one of theseparameters, such as signal to noise ratio, that once exceeded, or oncefalling below the threshold indicates the potential telemetry break ispresented. In one example monitoring the telemetry break conditionincludes determining a number of return errors from sent data packets.In another example, monitoring includes determining the number of badpackets received by the IMD and/or ED. As another example, theconnection criteria may include a change in the type of communication,such as a transition from a low/small payload communication (e.g., analert or command) to a high/large payload communication (e.g.,transferring EGM data from the IMD to the external device). As anotherexample, the connection criteria may include a change from a largerpayload communication to a smaller payload communication. For example, acommunication session may begin by downloading a software change,firmware update or other higher payload communication, in connectionwith which a higher data rate physical layer (e.g., LE 2 M) may be used.Once the software change or firmware update is completed it may bedesirable to continue a communication session but with a low/smallpayload communication, such as to confirm the operation of the softwarechange or firmware update. When switching to a lower payloadcommunication, the PHY may switch to the LE Coded 2S or 8S PHY (e.g.,while a series of tests are implemented to confirm the operation of thesoftware change or firmware update, in which commands are sent from theexternal device to the IMD and responses are returned).

At 506, one or more processors adjust the PHY utilized by the IMD and EDbetween small and large payload PHY, during the current session based onthe connection criteria. In one example the PHY is changed when apre-existing condition occurs, such as to increase the data rate from ahigher data rate to a lower data rate during a current session inresponse to a telemetry break, and increase the demand and datathroughput or another change in connection criteria. Alternatively, thePHY may be changed from a lower data rate to a higher data rate during acurrent session when the signal to noise ratio rises above a thresholdlevel during a current session, or a change in the data throughputincreases.

At 508, one or more processors increments a count of a number ofcommunications sessions that utilized the current PHY(s). In oneexample, when the one or more processors determine an in-session PHYtransition occurs from the higher data rate to a lower data rate, and inresponse thereto, the one or more processors increment the count of thenumber of sessions in which the IMD utilized the LE 1 M or LE Coded PHYthat support lower data rates. The increment can be represented by anumerical value, such as one, another numerical value, or the like. Theone or more processors optionally can determine if the count of thenumber of sessions in which the IMD utilized the lower data rate hasreached a threshold value; and in response to reaching the thresholdvalue, defined the starting PHY for the next communication session tocorrespond to the PHY that supports the lower data rate (e.g., startingwith the LE coded 2S PHY). Different measured events may result in thesame result to the count, such as adding one to a count, or may resultin a different result to the count.

At 510, the one or more processors adaptively learn a PHY level to beutilized to initiate a next session or certain types of sessionsfollowing the current session based on the counting of the number ofsessions. In one example, the one or more processors keep track of thecount at 508 and when the count reaches a threshold level, then when anext session begins the one or more processors automatically provide alower data rate PHY to start the next session. Optionally, when anon-telemetry break condition includes determining no return errors orbad packets were received by the IMD during the session, the count maybe decremented. In yet another example, multiple iterations of countscan occur. Specifically, a first count may provide the amount of times atelemetry break or other connection criteria occurs during sessionswhile a second count may provide the amount of times a signal to noiseratio or other connection criteria is below a threshold. By keepingtrack of the count of predetermined events that indicate theinterference level in a known environment, the one or more processorsare able to adaptively determine the start PHY for a given environmentand given data demand while keeping power usage low for otherenvironments and uses. Thus, the power usage (e.g., associated with theLE 2 M PHY) does not need to remain elevated at times when the elevatedpower level is unneeded (e.g., associated with the LE 1 M PHY).Consequently, power is saved, increasing battery life.

Thus, by utilizing the methodologies herein numerous advantages overother systems and methods are achieved. By utilizing a preferred PHYduring communication sessions, a better user experience resultsincluding having a more robust communication link, more immunity toambient interferences, and experience fewer interruptions to the link.By utilizing PHY and power switching, the system and methodology allowsthe device to switch to lower power when the link quality is good orwhen a communication session is not active. Consequently, powerconsumption is decreased, resulting in increased IMD life.

While the foregoing embodiments are described in connection with theBluetooth communications protocol, it is recognized that embodimentsherein may be implemented in connection with other communicationsprotocols that have multiple physical layers, where the multiplephysical layers have different corresponding data rates, error detectionor connection capabilities, signal qualities, power requirements and thelike.

CLOSING STATEMENT

It should be clearly understood that the various arrangements andprocesses broadly described and illustrated with respect to the Figures,and/or one or more individual components or elements of sucharrangements and/or one or more process operations associated of suchprocesses, can be employed independently from or together with one ormore other components, elements and/or process operations described andillustrated herein. Accordingly, while various arrangements andprocesses are broadly contemplated, described and illustrated herein, itshould be understood that they are provided merely in illustrative andnon-restrictive fashion, and furthermore can be regarded as but mereexamples of possible working environments in which one or morearrangements or processes may function or operate.

As will be appreciated by one skilled in the art, various aspects may beembodied as a system, method, or computer (device) program product.Accordingly, aspects may take the form of an entirely hardwareembodiment or an embodiment including hardware and software that may allgenerally be referred to herein as a “circuit,” “module” or “system.”Furthermore, aspects may take the form of a computer (device) programproduct embodied in one or more computer (device) readable storagemedium(s) having computer (device) readable program code embodiedthereon.

Any combination of one or more non-signal computer (device) readablemedium(s) may be utilized. The non-signal medium may be a storagemedium. A storage medium may be, for example, an electronic, magnetic,optical, electromagnetic, infrared, or semiconductor system, apparatus,or device, or any suitable combination of the foregoing. More specificexamples of a storage medium would include the following: a portablecomputer diskette, a hard disk, a random access memory (RAM), a dynamicrandom access memory (DRAM), a read-only memory (ROM), an erasableprogrammable read-only memory (EPROM or Flash memory), a portablecompact disc read-only memory (CD-ROM), an optical storage device, amagnetic storage device, or any suitable combination of the foregoing.

Program code for carrying out operations may be written in anycombination of one or more programming languages. The program code mayexecute entirely on a single device, partly on a single device, as astand-alone software package, partly on single device and partly onanother device, or entirely on the other device. In some cases, thedevices may be connected through any type of network, including a localarea network (LAN) or a wide area network (WAN), or the connection maybe made through other devices (for example, through the Internet usingan Internet Service Provider) or through a hard wire connection, such asover a USB connection. For example, a server having a first processor, anetwork interface, and a storage device for storing code may store theprogram code for carrying out the operations and provide this codethrough its network interface via a network to a second device having asecond processor for execution of the code on the second device.

Aspects are described herein with reference to the Figures, whichillustrate example methods, devices, and program products according tovarious example embodiments. These program instructions may be providedto a processor of a general purpose computer, special purpose computer,or other programmable data processing device or information handlingdevice to produce a machine, such that the instructions, which executevia a processor of the device implement the functions/acts specified.The program instructions may also be stored in a device readable mediumthat can direct a device to function in a particular manner, such thatthe instructions stored in the device readable medium produce an articleof manufacture including instructions which implement the function/actspecified. The program instructions may also be loaded onto a device tocause a series of operational steps to be performed on the device toproduce a device implemented process such that the instructions whichexecute on the device provide processes for implementing thefunctions/acts specified.

The units/modules/applications herein may include any processor-based ormicroprocessor-based system including systems using microcontrollers,reduced instruction set computers (RISC), application specificintegrated circuits (ASICs), field-programmable gate arrays (FPGAs),logic circuits, and any other circuit or processor capable of executingthe functions described herein. Additionally or alternatively, themodules/controllers herein may represent circuit modules that may beimplemented as hardware with associated instructions (for example,software stored on a tangible and non-transitory computer readablestorage medium, such as a computer hard drive, ROM, RAM, or the like)that perform the operations described herein. The above examples areexemplary only, and are thus not intended to limit in any way thedefinition and/or meaning of the term “controller.” Theunits/modules/applications herein may execute a set of instructions thatare stored in one or more storage elements, in order to process data.The storage elements may also store data or other information as desiredor needed. The storage element may be in the form of an informationsource or a physical memory element within the modules/controllersherein. The set of instructions may include various commands thatinstruct the modules/applications herein to perform specific operationssuch as the methods and processes of the various embodiments of thesubject matter described herein. The set of instructions may be in theform of a software program. The software may be in various forms such assystem software or application software. Further, the software may be inthe form of a collection of separate programs or modules, a programmodule within a larger program or a portion of a program module. Thesoftware also may include modular programming in the form ofobject-oriented programming. The processing of input data by theprocessing machine may be in response to user commands, or in responseto results of previous processing, or in response to a request made byanother processing machine.

It is to be understood that the subject matter described herein is notlimited in its application to the details of construction and thearrangement of components set forth in the description herein orillustrated in the drawings hereof. The subject matter described hereinis capable of other embodiments and of being practiced or of beingcarried out in various ways. Also, it is to be understood that thephraseology and terminology used herein is for the purpose ofdescription and should not be regarded as limiting. The use of“including,” “comprising,” or “having” and variations thereof herein ismeant to encompass the items listed thereafter and equivalents thereofas well as additional items.

It is to be understood that the above description is intended to beillustrative, and not restrictive. For example, the above-describedembodiments (and/or aspects thereof) may be used in combination witheach other. In addition, many modifications may be made to adapt aparticular situation or material to the teachings herein withoutdeparting from its scope. While the dimensions, types of materials andcoatings described herein are intended to define various parameters,they are by no means limiting and are illustrative in nature. Many otherembodiments will be apparent to those of skill in the art upon reviewingthe above description. The scope of the embodiments should, therefore,be determined with reference to the appended claims, along with the fullscope of equivalents to which such claims are entitled. In the appendedclaims, the terms “including” and “in which” are used as theplain-English equivalents of the respective terms “comprising” and“wherein.” Moreover, in the following claims, the terms “first,”“second,” and “third,” etc. are used merely as labels, and are notintended to impose numerical requirements on their objects or order ofexecution on their acts.

What is claimed is:
 1. An implantable medical device (IMD), comprising: a transceiver configured to communicate wirelessly, with an external device (ED), utilizing a protocol that utilizes multiple physical layers; the transceiver configured to transmit information indicating that the transceiver is configured with first, second and third physical layers (PHYs) for wireless communication; memory configured to store program instructions; one or more processors configured to execute instructions to: obtain an instruction designating one of the first, second and third PHY to be utilized for at least one of transmission or reception, during a communication session, with the external device; and manage the transceiver to utilize, during the communication session, the one of the first, second and third PHY as designated.
 2. The IMD of claim 1, wherein the transceiver is configured to transmit a communications packet represents at least one of an advertisement packet, a scan request packet or a scan response packet, the communications packet including the information indicating that the transceiver is configured with the first, second and third PHYs.
 3. The IMD of claim 1, wherein the transceiver is configured to receive an ED communications packet from the external device, the ED communications packet including the instruction designating the one of the first, second and third PHY.
 4. The IMD of claim 1, wherein the one or more processors are configured to at least one of 1) determine the type of communication or 2) determine a size of data set to be transferred between the ED and IMD, the one or more processors configured to generate the instruction designating the one of the first, second and third PHYs based on at least one of the type of communication or the size of the data set.
 5. The IMD of claim 4, wherein the protocol corresponds to a Bluetooth protocol, the first, second and third PHY corresponding to LE 1 M, LE 2 M and LE Coded PHYs, respectively, and the instruction designates the LE 2 M PHY when the type of communication corresponds to a large payload communication.
 6. The IMD of claim 5, wherein the instruction designates the LE Coded PHY when the type of communication corresponds to a small payload communication.
 7. The IMD of claim 1, wherein the one or more processors are configured to manage a receiver of the transceiver to utilize the first PHY in connection with receiving communications packets from the ED and to manage a transmitter of the transceiver to utilize the second PHY in connection with transmitting communications packets to the ED.
 8. An external device (ED) configured to wirelessly communicate with an implantable medical device (IMD) utilizing a protocol that supports multiple physical layers (PHYs), the ED comprising: an external transceiver configured to wirelessly communicate with the IMD; the external transceiver configured to receive a communications packet; memory configured to store program instructions; one or more processors that are configured, when implementing the program instructions, to: analyze the communications packet for information indicating whether the IMD is configured with multiple physical layers (PHYs) for wireless communication; select one of the multiple PHYs based on at least one of a type of communication to occur, or a size of a data set to be transferred, during a communication session; and transmit an instruction to the IMD to utilize the one of the multiple PHYs selected for at least one of transmission or reception during the communication session.
 9. The device of claim 8, wherein the one or more processors are further configured to receive, as the communications packet, an advertisement packet, and analyze a content of the advertisement packet for the information indicating where the IMD is configured with the multiple PHYs.
 10. The device of claim 8, wherein the information analyzed from the communications packet indicates whether the IMD is compatible with Bluetooth version 5.0 or higher.
 11. The device of claim 8, wherein the one or more processors are configured to determine the type of communication and select between first or second PHY based on the type of communication.
 12. The device of claim 11, wherein the one or more processors are configured to determine the size of the data set to be transferred and select between the second PHY or a third PHY based on the size of the data set to be transferred.
 13. The device of claim 8, wherein, following the select and transmit operations, the one or more processors are configured to manage the external transceiver to establish a communication session with the IMD utilizing the one of the multiple PHYs.
 14. The device of claim 8, wherein the one or more processors are configured to initiate a communication session utilizing a first PHY from the multiple PHY and, to change, during the communication session, to a second PHY from the multiple PHY.
 15. The device of claim 14, wherein the one or more processors change to the second PHY based on a connection criteria that includes at least one of a data throughput requirement, a communication type, a battery indicator, a telemetry break condition or link condition of the communications link between the IMD and ED.
 16. A method for managing a wireless communication between an external device (ED) and an implantable medical device (IMD) utilizing a protocol that supports multiple physical layers (PHYs), the method comprising: selecting, at one of the ED or IMD, one of multiple PHYs for wireless communication based on a connection criteria; and transmitting an instruction, to another of the ED or IMD, to utilize the one of the multiple PHYs selected for at least one of transmission or reception during the communication session.
 17. The method of claim 16, further comprising receiving, at the ED, a communications packet from the IMD; and analyzing the communications packet for information indicating whether the IMD is configured with multiple physical layers (PHYs) for wireless communication, the ED performing the selecting the one of the multiple PHYs and transmitting the instruction to the IMD.
 18. The method of claim 16, further comprising collecting and analyzing the connection criteria, the connection criteria including at least one of a data throughput requirement, a communication type, a battery indicator, a telemetry break condition or link condition of a communications link between the IMD and ED.
 19. The method of claim 16, further comprising determining at least one of 1) a type of communication or 2) a size of the data set to be transferred, and based thereon selecting the one of the multiple PHYs.
 20. The method of claim 19, further comprising establishing a communication session between the ED and the IMD utilizing the one of the multiple PHYs.
 21. The method of claim 16, further comprising initiating a communication session utilizing a first PHY from the multiple PHY and, changing, during the communication session, to a second PHY from the multiple PHY. 